3rd Update: Weitchpec earthquake upgraded to a 5.6

A 5.6-magnitude earthquake rattled Humboldt County shortly after 1 p.m. today, striking about 18 miles northeast of Trinidad.

According to the United States Geological Survey, the quake registered a 5.6 and was felt at 1:07 p.m. The quake registered at depth of about 20 miles, and struck 31 miles northeast of Eureka.

Juice, bottles of pasta sauce and other items topple off shelves at Ray's Food Place in Hoopa, but the quake didn't do major damage, said store Manager David Gillan. There were about 10 to 15 customers shopping at the time.

Gillan said the shaking lasted about five seconds and he closed the store for roughly 10 minutes to clean up the aisles. "When I got downstairs everybody was moving toward the front," he said. "We moved them out of the store for general safety."

National Weather Service Spokesman Troy Nicolini said he received reports from people who felt the earthquake but had no damage. The earthquake "was too small and too far inland" to warrant any tsunami concerns, Nicolini said.

The earthquake occurred about 20 miles beneath the earth's surface, which is typical for Humboldt County's inland earthquakes, said HSU geology professor Lori Dengler. The quake occurred on a fault that is unnamed because it doesn't reach the surface. Humboldt County is full of unnamed faults that either haven't been studied or can't be seen, she said.

Monday's earthquake is similar to a magnitude 5.4 earthquake that struck east of Willow Creek in 2008 about 18 miles beneath the earth's surface, Dengler said.

"It was widely felt, but it didn't do any damage partly because it's in a remote rural area and partly because it's deep," she said. "It's still 20 miles away from (the surface). That's one of the good things about these deeper earthquakes."

No serious damage reported yet. Originally reported as a 5.3-magnitude, it was upgraded shortly before 1:20 p.m.